What is Antimatter and why is it the most expensive substance on Earth

Antimatter refers to an interesting concept in physics. It is considered to be the opposite of ordinary matter, and every particle of matter is believed to have an antiparticle of the same mass but opposite charge. For instance, a positron is the antiparticle of the electron. This means that a positron owns a positive charge whereas the electron possesses a negative charge. That makes this material a mirror image of the matter making up our universe.